Sea urchin spines
May inspire new materials
Many beach trips have been spoiled by stepping on the sharp and strong spines of sea urchins. The urchin uses those spines for moving around and protection against predators. However, recently biologists and engineers from Australian universities have analyzed their ingenious structures under a powerful tool called micro-computed tomography (microCT).1
Each spine is a single crystal of calcite (CaCO3). This is normally a soft and brittle mineral, but it is highly strengthened in several ways. It is a hollow tapered cylinder, which saves weight and materials without sacrificing much strength. Some magnesium ions replace calcium ions, which produce an irregularity that impedes cracks from propagating (the same principle explains the greater strength of metal alloys). So any fractures are more like in glass, a non-crystalline solid, than a crystal. This fracturing absorbs energy and protects the main spherical shell (called a test) of the animal.
There is also a small amount of organic material (glycoprotein) with the mineral crystal, which makes a huge difference to toughness.2
The strength is further enhanced by its very fine structure. The crystal contains finely spaced radial wedges connected by bridges. The thin edges direct stresses to the outside, and the spaces stop fractures from spreading through the whole spine. The researchers say, “Overall, the spine is highly porous with an intricate structural hierarchy.”3
However, in a popular report, the researchers paid the obligatory fact-free homage to evolution. They called this amazing structure an “evolutionary feature” that was “optimized” and “survived hundreds of millions of years”. Yet they also say “the finding could offer clues for creating new bio-inspired materials and more efficient engineering designs.” This should have been a clue that the original was designed as well!
References and notes
- Tsafnat, N., Micromechanics of Sea Urchin Spines, PLoS ONE 7(9):e44140, 2012 | doi:10.1371/journal.pone.0044140. Return to text.
- This mineral/protein combination is also largely responsible for the toughness of abalone and conch shells—see Sarfati, J., Amazing abalone armour Creation 30(1):44–45, 2007; creation.com/abalone and Super shells, Creation 27(3):19, 2005; creation.com/conch. Return to text.
- Gough, M., Engineering of sea urchins revealed, Engineers Australia, p. 13, January 2013. Return to text.
I agree Jonathan. Obviously the logic is clear, the more brilliantly sophisticated and intelligent a design is, the more sophisticated and intelligent a designer has to be because you require something that has the MATCHING ability.
For example, to create a few basic Plasticine figurines, with basic blob-heads, the requirement would be a basic level of designer such as a child. As the sophistication grows, so must the cause have the matching ability to create.
It strikes me as rather obvious that evolution, having no mind at all to even create a basic figurine, has no matching designer-abilities.
If even a basic Plasticine figurine requires SOME intelligence, then an omniscient-level design requiring NONE, breaks the law of non-contradiction, in my opinion for that is to state that the cause would NOT have the matching ability. It is a contradiction because as your article shows, the level of design is the very best, so the designer also has to have the very best matching ability.